The present invention relates to a venting device for venting the housing of a rotary machine.
As the rotor of a rotary machine rotates inside a housing, the lubricating oil and/or working fluid or oil or other liquid in the housing and located at the rotor is broken up into small droplets, which create a mist in the housing. A typical venting device for venting the mist laden atmosphere of the housing has a vent duct leading from inside the housing out through a liquid-mist or oil-mist separator or filter and has means for directing at least a portion of the mist laden atmosphere or air from the inside of the housing through the vent duct to the mist separator.
Rotary machines in which such venting devices are used include, for example: gear arrangements in which the rotor is a gear; a clutch enclosed in a housing, and particularly a hydrodynamic clutch, in which the rotor is formed by one of the clutch halves; units in which a clutch, which is preferably of a hydrodynamic nature, is combined with gear drives.
In such rotary machines, oil may be used as a lubricant and as a power transmission fluid, or both. When such a machine operates at high rotary speeds, atomizing of the oil takes place. Furthermore, pressure is developed within the housing so that the housing atmosphere which is laden with an oil-mist penetrates outward through the shaft packings contained in the housing. Part of the oil is lost as it drips from the packing rings, and the air surrounding the device may be contaminated with oil.
For these reasons, it is known to provide a venting duct from the housing having an oil-mist separator in it, so that the pressure within the housing can be substantially reduced. In previously known rotary machines, the venting duct is passed through the housing wall and the oil-mist separator is placed on the housing. The oil-mist separator typically comprises a filter cartridge arranged in a filter pot. The resistance to flow exerted by the filter can assume a considerable value, depending upon the filter material used, particularly if a high degree of purity of the discharged air is desired. In such cases, it is frequently necessary to associate a blower with the oil-mist separator. This manner of construction is, however, expensive and energy is continuously required for driving the blower. Such an arrangement is shown in U.S. Pat. No. 3,633,341.
Another known venting device shown in West German Unexamined Application (Offenlegungsschrift) No. 26 43 767, at FIG. 3, satisfies only moderate requirements. In that case, the venting duct is passed outward through the rotor shaft. An oil-mist filter is also arranged within the rotor shaft. No conveying device for the air to be discharged is provided in this case.